{
  "model": "claude-sonnet-45",
  "response": "# Palindrome Detection in Python\n\nHere's a comprehensive Python solution for palindrome detection with multiple approaches and test cases:\n\n## Solution 1: Basic String Reversal\n\n```python\ndef is_palindrome_basic(text: str) -> bool:\n    \"\"\"\n    Check if a string is a palindrome by comparing it to its reverse.\n    This approach is simple but creates a new string.\n    \"\"\"\n    # Remove non-alphanumeric characters and convert to lowercase\n    cleaned = ''.join(char.lower() for char in text if char.isalnum())\n    return cleaned == cleaned[::-1]\n```\n\n## Solution 2: Two-Pointer Approach (Optimized)\n\n```python\ndef is_palindrome_two_pointer(text: str) -> bool:\n    \"\"\"\n    Check palindrome using two pointers without creating new strings.\n    More memory efficient for large inputs.\n    \"\"\"\n    left, right = 0, len(text) - 1\n    \n    while left < right:\n        # Skip non-alphanumeric characters from left\n        while left < right and not text[left].isalnum():\n            left += 1\n        # Skip non-alphanumeric characters from right\n        while left < right and not text[right].isalnum():\n            right -= 1\n        \n        if text[left].lower() != text[right].lower():\n            return False\n        \n        left += 1\n        right -= 1\n    \n    return True\n```\n\n## Solution 3: Recursive Approach\n\n```python\ndef is_palindrome_recursive(text: str, left: int = 0, right: int = None) -> bool:\n    \"\"\"\n    Recursive palindrome check. Good for teaching recursion concepts.\n    \"\"\"\n    if right is None:\n        right = len(text) - 1\n    \n    # Base case: we've checked all characters\n    if left >= right:\n        return True\n    \n    # Skip non-alphanumeric characters\n    if not text[left].isalnum():\n        return is_palindrome_recursive(text, left + 1, right)\n    if not text[right].isalnum():\n        return is_palindrome_recursive(text, left, right - 1)\n    \n    # Compare characters (case-insensitive)\n    if text[left].lower() != text[right].lower():\n        return False\n    \n    # Recursive call for next pair\n    return is_palindrome_recursive(text, left + 1, right - 1)\n```\n\n## Comprehensive Test Suite\n\n```python\nimport unittest\n\nclass TestPalindromeDetection(unittest.TestCase):\n    \n    def test_basic_palindromes(self):\n        test_cases = [\n            (\"racecar\", True),\n            (\"A man, a plan, a canal: Panama\", True),\n            (\"hello\", False),\n            (\"\", True),  # Empty string is palindrome\n            (\"a\", True),  # Single character\n            (\"No 'x' in Nixon\", True),\n            (\"Was it a car or a cat I saw?\", True),\n        ]\n        \n        for text, expected in test_cases:\n            with self.subTest(text=text):\n                self.assertEqual(is_palindrome_basic(text), expected)\n                self.assertEqual(is_palindrome_two_pointer(text), expected)\n                self.assertEqual(is_palindrome_recursive(text), expected)\n    \n    def test_edge_cases(self):\n        # Numbers and symbols\n        self.assertTrue(is_palindrome_basic(\"12321\"))\n        self.assertTrue(is_palindrome_basic(\"@#$%^&*()(*&^%$#@\"))\n        \n        # Mixed case\n        self.assertTrue(is_palindrome_basic(\"RaceCar\"))\n        self.assertTrue(is_palindrome_basic(\"MaDaM\"))\n    \n    def test_performance(self):\n        # Large palindrome\n        large_palindrome = \"a\" * 10000 + \"b\" + \"a\" * 10000\n        self.assertTrue(is_palindrome_two_pointer(large_palindrome))\n\nif __name__ == \"__main__\":\n    unittest.main()\n```\n\n## Performance Analysis\n\n1. **Basic Reversal**: O(n) time, O(n) space - Simple but creates new string\n2. **Two-Pointer**: O(n) time, O(1) space - Most memory efficient\n3. **Recursive**: O(n) time, O(n) space (call stack) - Elegant but limited by recursion depth\n\n## Recommendations\n\n- Use **two-pointer approach** for production code (most efficient)\n- Use **basic reversal** for readability and simple cases\n- Use **recursive approach** for educational purposes\n\nAll functions handle:\n- Case insensitivity\n- Ignoring non-alphanumeric characters\n- Empty and single-character strings\n- Unicode characters (Python 3 handles this naturally)\n\nChoose based on your specific needs!\n",
  "tokens_used": 1247,
  "cost": 0.0032,
  "latency_ms": 1450,
  "success": true
}